The Pilot

The first series features Christopher Eccleston as the ninth incarnation of the Doctor, his only series in the role, accompanied by Billie Piper, as his first and main companion Rose Tyler, whom he plucks from obscurity on planet Earth, and to whom he grows increasingly attached. He also travels briefly with unruly boy-genius Adam Mitchell, played by Bruno Langley, and with 51st-century con man and former "Time Agent" Captain Jack Harkness, portrayed by John Barrowman. Episodes in the series form a loose story arc, based upon the recurring phrase "Bad Wolf".

This is the first series to feature David Tennant as the tenth Doctor. He continues to travel with his companion Rose Tyler (Billie Piper), with whom he has grown increasingly attached. They also briefly travel with Rose's boyfriend Mickey Smith (Noel Clarke), and Camille Coduri reprises her role as Rose's mother Jackie. The series is connected by a loose story arc consisting of the recurring word "Torchwood". This is also the first series to be preceded by a Christmas special, which was commissioned to see how well the show could do at Christmas. The success of "The Christmas Invasion" led to the Christmas special becoming an annual tradition.

The series stars David Tennant as the Doctor. In the Christmas special he is joined by Catherine Tate as Donna Noble. The series also introduces Freema Agyeman as the Doctor's new companion Martha Jones. John Barrowman also reprises his role as Captain Jack Harkness in the final three episodes which serve as the finale. The series is connected by a loose story arc consisting of the recurring phrase "Vote Saxon".

Adventures in time and space with the Tenth Doctor and his companion Donna Noble.

This is the first series to feature Matt Smith as the eleventh incarnation of the Doctor. Karen Gillan is introduced as the Doctor's new companion, Amy Pond. Alex Kingston returns as River Song, a mysterious woman from the Doctor's future who summons him twice. The main story arc concerns a pattern of cracks in the universe that are sometimes unnoticed by the characters. It is discovered that the cracks can erase things from existence.

The Doctor returns, alongside newly weds Amy and Rory, to face monsters and mysteries and adventures all across time and space. Together they find themselves in sixties America, battling the invasion the world forgot, then aboard a pirate ship on the high seas of 1696, to solve the mystery of the Siren. In a bubble universe at the edge of reality, the Doctor meets an old friend with a new face.

The main story arc of the series focused on the significance of the character of Clara, whom the Doctor had encountered twice before as Oswin in "Asylum of the Daleks" and as a governess in "The Snowmen". It also features the recurring appearance of the Doctor's enemy, The Great Intelligence.

The series is the first to star Peter Capaldi as the Twelfth Doctor and Jenna Coleman as his companion, Clara Oswald. Also playing a major recurring role in the series is Samuel Anderson as Danny Pink, Clara's boyfriend. The main story arc revolves around a mysterious woman called Missy (portrayed by Michelle Gomez), who is often seen welcoming people who have died throughout the series to the "Promised Land", a place that serves as an apparent afterlife to deceased characters.

Now that the Doctor and Clara have established a dynamic as a partnership of equals, they’re relishing the fun and thrills that all of space and time has to offer. Tangling with ghosts, Vikings and the ultimate evil of the Daleks, they embark on their biggest adventures yet. Missy is back to plague the Doctor once more, the Zygons inspire fear as they shape-shift into human clones, and a new arrival moves in cosmic ways.

The series introduces Pearl Mackie as Bill Potts, and also features Matt Lucas as Nardole. Michelle Gomez and John Simm return as their respective incarnations of the Master. The main story arc for the first half of the series revolves around the Doctor and Nardole occupying themselves at a university while they guard an underground vault containing Missy. Missy later travels with the team in the TARDIS, and eventually partners with her previous incarnation as they battle a Cyberman onslaught.

Series 11 follows the Thirteenth Doctor as she initially searches for her lost TARDIS, inadvertently bringing Graham, Ryan, and Yasmin with her on her travels. All three later contemplate returning to their normal lives but decide to continue travelling with the Doctor.

The series follows the Thirteenth Doctor and her companions as they meet a new incarnation of the Master, and his destruction of Gallifrey, the return of Jack Harkness, the appearance of an unknown incarnation of the Doctor, the Cybermen, and the secret of the "Timeless Child". Jodie Whittaker returns for her second series as the Thirteenth Doctor. It also stars Bradley Walsh, Tosin Cole and Mandip Gill as the Doctor's travelling companions, playing Graham O'Brien, Ryan Sinclair and Yasmin Khan, respectively.

From Liverpool to the depths of space, via the Crimean war and a planet named Atropos which shouldn’t even exist, fighting old foes and new creatures from beyond our dimension, the Doctor and company face a race against (and through!) time to uncover a universe-spanning mystery: what is the Flux?